At low temperature (\(T<0.5\)  K), SrTiO\(_3\)  displays a striking superconductive behavior with low carrier concentration [1]}, [2]}.
Notably, this superconducting phase is characterized by the competition of isotope oxygen doping and quantum fluctuation of the transverse optical (TO) soft phonon mode.
Both compete for the formation of electron pairing and ferroelectricity, a mechanism known as quantum criticality [3]}, [4]}, [5]}.
The microscopic details of the superconducting phase and quantum criticality in SrTiO\(_3\)  are still debated [6]}, [7]}.
These quantum fluctuations, however, play an important role even for the ground state, where they are decisive in a competition between ferro- and paraelectricity.
